Feeding mechanism for grinding machines



Jan. 4, 1944. W F. FRASER 2,338,631

FEEDING MECHANISM For'i GRINDING MACHINES Filed Aug. 29, 1940 3 sheets sheet 1.

Inven'l'or i W EMI Jan, 4, 1944. N w. F. FRASER 2,338,631,

FEEDING MECHANISM FOR GRINDING MACHINES Filed Aug. 29, 1940 3 Sheets-Sheet 2 j" Y Q E mvzmol I Sheets-Sheet 3 F. FRASER FEEDING MECHANISM 'FOR GRINDING MACHINES 1 Filed Aug. 29, 1940 Jan. 4,1944;

NTOR

' a INVE 'ATT ORNEY.

Patented Jan. 4, 1944 UNITED STATES PATENT OFFICE FEEDING MECHANISM FOR GRINDING MACHINES 3 Claims.

This invention relates to grinding machines, and is more especially concerned with such machines of the type known as rotary surface grinders.

A machine of this character usually comprises a rotary chuck or support on which the work to be ground is held and revolved, a grinding wheel or equivalent abrading element, a wheel head supporting said wheel for traversing movement across the surface of the chuck, and suitable supporting and driving mechanism for said chuck, wheel and wheel head. In using such a machine a piece of work to be ground such, for example, as a bearing disk, collar, or the like, is centered on the chuck and is revolved rapidly while the grinding wheel is reciprocated toward and from the axis of the chuck. The relative movement of the chuck and grinding wheel in a direction transverse to the reciprocating movement of the wheel for the purpose of feeding the work to the wheel, is customarily produced either by hand or automatically, and the present invention is primarily concerned with an automatic feeding mechanism for performing this function. It aims to improve mechanisms of this character with a view to simplifying their construction while at the same time producing an exceptionally accurate, reliable and easily controlled feeding apparatus.

The nature of the invention will be readily understood from the following description when read in connection with the accompanying drawings, and the novel features will be particularly pointed out in the appended claims.

In the drawings,

Figure l is a view, partly in side elevation and partly in vertical section, illustrating those portions of a rotary surface grinder with which this invention is more especially concerned, some of the parts being broken away and some being indicated diagrammatically;

Fig. 2 is a similar View of the mechanism provided by this invention for giving the chuck a work feeding movement;

Fig. 3 is a vertical, sectional view of parts of the mechanism shown in 2; and

Fig. 4 is a sectional view approximately on the line 4-4, Fig. 3.

The drawings show the invention as applied to the grinding machine illustrated in my prior Patent No. 2,018,847, granted October 29, 1935, and reference should be made to this patent for an understanding of the general organization of the machine. Those parts with which the present invention is more especially concerned comprises a rotary chuck 2 mounted to revolve about a vertical axis and a grinding wheel 3 supported in a wheel head 4 and mounted to reciprocate horizontally across the surface of the chuck. In the construction shown in said patent the reciprocating movement of the wheel head is produced hydraulically, the head being equipped with a piston which runs in a cylinder 31, and the admission of fluid under pressure alternately to the opposite ends of this cylinder being controlled by a reversing valve 36. In that machine, also, provision is made for moving the chuck 2 up and down, the construction comprising a' bracket or knee 94 supporting the chuck assembly and itself supported to slide vertically in ways formed in the machine frame, the feeding movement being produced through the rotation of a screw 91, Fig. 2. The operating mechanism for this screw includes a ratchet wheel 95 mounted fast on a horizontal shaft S which is connected through the worm drive 96 with the screw shaft 97. A hand wheel W also is secured fast to the ratchet wheel 95. Consequently, by revolving either of the members W or 95, the chuck 2 may v be moved up or down, depending upon the direction of rotation of said members. All of the reference numerals above referred to (but not the letters) designate corresponding parts in the patent above mentioned.

The present invention provides a very simple but positively operating mechanism for producing the step by step rotative movements of the wheel '95, and consequently'of the screw 91, necessary to feed the work at the desired times and to the desired degrees necessary to the operation of the I machine on the work. For example, a typical operating condition requires that the chuck 2 be function comprises a pawl 5, Figs. 2 and 3, pivoted at 6 on the upper end of a lever 1 which is fulcrumed on the stud 8 fixed in the bracket structure 94. Secured rigidly to this lever is an arm I0 which rests on the upper surface of a cam l2 and this cam is secured fast to the end of a rock shaft l3. The shaft projects through, and is journaled in, the opposite parallel walls of the casing I4, best shown in Figs, 3 and 4, and

'ment to accommodate a blade or vane I is secured fast to the shaft and fits snugly between the lateral and circumferential walls of the casing. Also located between these lateral walls is a filler block l6 closing approximately half of the circular space in the casing and thus providing a substantially semi-circular chamber N3 in which the vane or blade l5 can oscillate. Pipes lT-I'l, Figs. 1 and 4, lead from the reversing valve 36 to the chamber l8 at opposite sides of thevane l5, and these connections are so made that fluid under pressure is delivered alternately to the opposite sides of the vane simultaneously with the similar delivery of fluid to the opposite ends of the cylinder 3'.

for the purpose of operating the wheel head.

It will be evident from the foregoing that the vane I5 is oscillated in one direction or the other 7 simultaneously with the reversal in movement of the wheel head, the connections being made to the reversing valve 36 at such points that the movements of the'vane are produced at the ends cfthe stroke of the wheel. At other times the vane remains at rest. late the shaft 13 and consequently rock the cam -12, first in one direction and then in the other,

These .movements oscil and they are transmitted-through the arm ID to the lever 1 and operate the'pawl 5, thu causing .it to liftthe chuckZ step by step.

' In orderto adjust the amplitude of the work feeding movements so produced, two adjusting screws 26 and 2!, Fig.2, are mounted on the casin position to engage, respectively, the oppofsitelends or arms ofa stop member 22 which is keyed to the shaft 13'. By adjusting these screws the limits of the oscillating movement of the vane and, consequently, of'the cam [2, can be varied as desired to produce just the degree of feeding movement required.v In addition, this feeding movement of the chuck can be reduced to .zero at either end of the stroke, if desired, by suitable adjustment of one or the other of the screws 29 or 2i, or it can be increased up to any value within the limits'of the design of the ma chine.

By means of such a mechanism as that herein shown and described, the operation of feeding the work to the wheel may be performed automatical- :ly with a high degree of precision and the feeding movements may be so timed with reference to those of the wheel head as to take place in the desired relationship to such movements. The mechanism may be manufactured and installed economically and it has ample range of adjustthe requirements of a wide variety of work.

While I haveherein shown-and described a preferred embodiment of my invention, it will be under tood that the invention is susceptible of embodiment in other forms without departing from the spirit or scope thereof.

' mechanism Having thus described my invention, what I desire to claim as new is:

1. In a grinding machine, the combination of a rotary grinding wheel, a reciprocating wheel head in which said wheel is mounted, a support for holding the work while it is operated upon by said wheel, mechanism for reciprocating said wheel head to move said wheel forward and backward across the face of said support, screwthreaded mechanism for moving said support to feed the work to the wheel, a pawl and ratchet for driving said screw-threaded mechanism step by step, an oscillating cam for actuating the pawl of said pawl and ratchet mechanism, hydraulically actuated means for oscillating said cam in timed relationship to the movements of said wheel head, and controlling mechanism for said hydraulically actuated means adjustable to regulate the movements of said cam to produce such movements at either or both ends of the stroke of the wheel head.

2. In a grinding machine, the combination of a rotary. grinding wheel, a reciprocating wheel head in which said wheel is mounted, a rotary support for holding and revolving the work while it is operated upon by said Wheel, hydraulic means for reciprocating said wheel head to move said wheel forward and backward across the face of said support, screw-threaded mechanism for moving said work support to feed the work to the wheel, a ratchet wheel operatively connected with said screw-threaded mechanism to drive it, a pawl for operating said ratchet wheel, a vane mounted to swing about an axis, a casing in which said vane is operatively supported, means for supplying fluid under pressure alternately to said casing atopposite sides of said vane to operate it at the ends of the stroke of said wheel head, a shaft arranged to be oscillated by said vane, a'cam fast on said shaft, and a lever arranged to be actuated by saidcam in both directions of oscillation of the cam, said lever being connected with said pawl to operate it.

3. In a grinding machine, the combination of a rotary grinding wheel, a reciprocating wheel head in which said wheel is mounted, a rotary support for holding and revolving the work while it is operated upon by said wheel, hydraulic means for reciprocating said wheel head to move said wheel forward and backward across the face of said support, screw-threaded mechanism for moving said work support to feed the work to the wheel, a ratchet wheel operatively connected with said screw-threaded mechanism to drive it, a pawl for operating said ratchet wheel, a vane mounted to swing about an axis, a casing in whichsaid vane is operatively supported, means for supplying fluid under pressure alternately to said casing at opposite sides of said vane to operate it at the ends of the stroke of said wheel head, a shaft arranged to be oscillated by said vane, a cam driven by said shaft, a lever arranged to be operated by said cam in both directions of oscillation of the cam, said lever carrying said pawl, and means operable to adjust the limits of the oscillating movement of said vane.

WARREN F. FRASER. 

